1. Field of the Invention
This invention relates to an appliance for use in excising skin samples from stretched skin, e.g. to a skin biopsy appliance.
2. Description of Prior Art
It frequently is necessary in the practice of medicine to excise a skin sample from a given skin area. An example of such a procedure is the excising of skin samples in the performance of biopsies.
As is well known, a biopsy is a surgical procedure performed on the skin or other organ to sample tissue structure and cell content, usually to assist in disease diagnosis.
A skin biopsy may be accomplished in different ways. For instance, a scalpel blade may be used to cut into the skin and excise samples of various sizes. This procedure almost always requires suturing the wound edges together.
In the alternative, the biopsy sample may be obtained by slicing or shaving the skin horizontally to remove an elevated portion. This procedure usually does not require suturing.
The method of sampling skin tissue most often used by dermatologists relies upon the use of an instrument called a skin punch. This is a short, pencil-shaped tool having one end in the form of an open cylinder provided with a sharp, cutting blade. The punch is held at its upper, solid end by the thumb and one or two fingers and twirled while it rests on and is pressed lightly into the skin surface. This creates a plug of tissue which can be snipped loose from its underlying attachment and submitted to the laboratory for examination.
The punch biopsy routine may or may not require suturing. If the defect is only 1-3 mm in diameter, natural and unassisted healing usually will be adequate. However, if the defect is larger, suturing will hasten the healing. It also will result in the formation of a less conspicuous scar.
Although widely used, the foregoing procedure has a significant disadvantage. The biopsy punch inherently cuts a circular opening in the skin. When the edges of a circular opening are brought together, the distal portions splay out and pucker to form nipple-like protrusions. The resulting scar is unsightly and cosmetically undesirable.
To overcome this problem, a procedure has been developed which takes advantage of the fact that there exist in the skin variously disposed lines of natural skin tension. These are called "Langer's lines". They may be taken advantage of to create in the skin an elliptical opening rather than a circular one. The elliptical opening is readily amenable to effective suturing procedures.
Accordingly, to carry out the skin sampling procedure a lateral stretching force is applied to the skin in the skin sampling area. This force is applied in the direction perpendicular to the lines of greater tension.
The stretched skin then is incised to make a substantially round cut defining the sample. The stretching force is removed and the sample excised by cutting or snipping it away from the anchoring tissue.
As this is done, the opening in the skin, which originally is circular, becomes elliptical. This is owing to deformation by the lines of tension (Langer's lines) which exist in the skin. As noted, the elliptical opening may be sutured effectively.
However, even this improved technique is characterized by a problem the solution to which is the object of the present invention.
In carrying out a punch biopsy, the surgeon normally stretches the skin in the biopsy area by applying stretching force perpendicular to Langer's lines with the thumb and forefinger of one hand while manipulating the biopsy punch with the other hand. It is the surgeon's intention to maintain the stretching tension for the entire duration of the sampling procedure.
In practice, this may be difficult to do.
First, because of absorption in his work, distraction, fatigue, inattention, or other disturbing factors, the surgeon at the critical moment of taking the biopsy sample may relax the skin-stretching pressure, or his fingers may slip. As a result, the punched out opening ("defect") in the skin assumes a round configuration rather than the desired elliptical configuration.
Secondly, the surgeon for any of the above reasons may apply the stretching force in a direction other than the desired direction precisely perpendicular to the Langer's lines. In either case, the result is the same. The desired elliptical skin opening is not obtained.
An appliance and method for overcoming the foregoing problem is set forth in my U.S. Pat. No. 5,123,907. While the appliance and procedure described therein successfully overcome the problem, it remains to provide an appliance and method which give the surgeon a view of the skin area which underlies the appliance so that he can position the appliance accurately and study the unique disease characteristics of the underlying skin.
It also remains to provide a method and appliance which permits tissue exudate and serum to escape during the surgical procedure. Otherwise, an accumulation of this material lubricates the underside of the appliance and causes it to slip out of position.
Still further, it remains to provide a method and appliance which, independently of any applied adhesive material to the skin-contacting surfaces of the appliance, provides an anchoring function which anchors the appliance temporarily in place throughout the entire surgical procedure.
It is the general purpose of the present invention to provide such an appliance and method.